Bearing diagnostic apparatus and method for diagnosing bearing

Abstract

To provide a bearing diagnostic apparatus and a method for diagnosing a bearing capable of estimating the occurrence of flaking.SOLUTION: The apparatus includes: an envelope-processing unit for performing envelope processing on a vibration signal acquired by a vibration sensor; a frequency-analysis processing unit for performing a fast Fourier transform on a time-domain signal after the envelope processing to convert the signal into a frequency-domain signal including respective signal intensities for frequencies; and a determination-processing unit for estimating the occurrence of flaking on the basis of a signal intensity n2 of an even-order harmonic of a damage frequency caused by damage generated at least on a raceway surface of a bearing.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a bearing diagnostic device and a bearing diagnostic method. [Background technology]

[0002] Patent Document 1 discloses a condition monitoring device and a condition monitoring method for monitoring the condition of a rotating part that rotates relative to a stationary part. This patent document 1 describes a method and configuration for acquiring bearing vibrations, performing envelope processing and frequency analysis processing, and diagnosing the presence or absence of abnormalities such as scratches at the vibration level of the natural vibration frequency, identifying the abnormal part, and diagnosing the degree and progression of damage, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-32520 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the fatigue life of a rolling bearing is defined as the total number of revolutions until scale-like spalling (hereinafter also referred to as "flaking") occurs on the surface of the raceway surface. Large machinery and equipment, specifically bearings used in main shaft bearings and generator bearings in wind power generators, cannot be easily replaced, so more planned operation is required while allowing flaking to progress. Flaking progresses rapidly when the spall size in the rotational direction on the raceway surface exceeds one pitch (the distance between adjacent rolling elements, hereinafter also referred to simply as "the distance between rolling elements"). Therefore, it is necessary to estimate the occurrence of flaking before the spall size in the rotational direction on the raceway surface reaches one pitch.

[0005] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a bearing diagnostic device and a bearing diagnostic method that are capable of estimating the occurrence of flaking. [Means for solving the problem]

[0006] In order to achieve the above object, a bearing diagnostic device according to one aspect of the present invention is a bearing diagnostic device that diagnoses the condition of bearings installed in mechanical equipment, and includes: an envelope processing unit that performs envelope processing on vibration signals acquired by a vibration sensor; a frequency analysis processing unit that performs fast Fourier transform processing on the time domain signal after envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; and a determination processing unit that estimates the occurrence of flaking based on the signal strength of at least even multiple waves of the damage frequency caused by damage that has occurred on the raceway surface of the bearing.

[0007] The above configuration makes it possible to estimate the occurrence of flaking on the raceway surface of the bearing that reaches half the distance between the rolling elements, thereby making it possible to determine the need for bearing replacement before the damage to the bearing progresses to the point where it becomes unusable.

[0008] In a preferred aspect of the bearing diagnosis device, the determination processing unit calculates the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired.

[0009] This makes it possible to calculate the damage frequency according to the operating conditions of the bearing.

[0010] In a preferred embodiment of the bearing diagnostic device, the determination processing unit may be configured to estimate that flaking has occurred when a peak value of signal intensity within a predetermined range that includes even multiples of the damage frequency exceeds a predetermined threshold.

[0011] In a preferred embodiment of the bearing diagnostic device, the determination processing unit defines the peak value of the signal strength within a predetermined range that includes the damage frequency or an odd-numbered multiple of the damage frequency as n1, and the peak value of the signal strength within a predetermined range that includes an even-numbered multiple of the damage frequency as n2, and preferably estimates that flaking has occurred when the ratio expressed as n2 / n1 exceeds a predetermined threshold.

[0012] With the above configuration, it becomes easier to detect when the size of flaking in the rotational direction approaches half the distance between the rolling elements, thereby improving the accuracy of estimating flaking.

[0013] In a preferred embodiment of the bearing diagnostic device, the determination processing unit defines an integrated value of signal strength within a predetermined range that includes the damage frequency or odd-numbered harmonics of the damage frequency as S1, and an integrated value of signal strength within a predetermined range that includes even-numbered harmonics of the damage frequency as S2, and preferably estimates that flaking has occurred when the ratio expressed as S2 / S1 exceeds a predetermined threshold.

[0014] This makes it easier to detect when the size of flaking in the rotational direction approaches half the distance between the rolling elements, thereby improving the accuracy of estimating flaking.

[0015] In a desirable aspect of the bearing diagnostic device, the determination processing unit may be configured to estimate that flaking has occurred when the integrated value of signal strength across the entire region of the frequency domain signal is S, the peak value of signal strength within a predetermined range that includes even multiples of the damage frequency is n2, and the ratio expressed as n2 / S exceeds a predetermined threshold value.

[0016] In a preferred embodiment of the bearing diagnostic device, the determination processing unit may be configured to define an integrated value of signal strength across the entire frequency domain signal as S, define an integrated value of signal strength within a predetermined range including even multiples of the damage frequency as S2, and estimate that flaking has occurred when a ratio expressed as S2 / S exceeds a predetermined threshold value.

[0017] In a desirable aspect of the bearing diagnostic device, the determination processing unit may be configured to estimate that flaking has occurred when the effective value of the vibration signal is R, the peak value of the signal strength within a predetermined range that includes even multiples of the damage frequency is n2, and the ratio expressed as n2 / R exceeds a predetermined threshold value.

[0018] In a desirable aspect of the bearing diagnostic device, the determination processing unit may be configured to denote the effective value of the vibration signal as R, denote the integrated value of signal strength within a predetermined range that includes even multiples of the damage frequency as S2, and estimate that flaking has occurred when the ratio expressed as S2 / R exceeds a predetermined threshold value.

[0019] A bearing diagnostic method according to one aspect of the present invention is a bearing diagnostic method for diagnosing the condition of bearings installed in mechanical equipment, and includes: an envelope processing step of performing envelope processing on a vibration signal acquired by a vibration sensor; a frequency analysis processing step of performing fast Fourier transform processing on the time domain signal after envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; and a determination processing step of estimating the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing.

[0020] The above configuration makes it possible to estimate the occurrence of flaking on the raceway surface of the bearing that reaches half the distance between the rolling elements, thereby making it possible to determine the need for bearing replacement before the damage to the bearing progresses to the point where it becomes unusable.

[0021] In a preferred embodiment of the bearing diagnosis method, the method preferably further comprises a damage frequency calculation step of calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired.

[0022] This makes it possible to calculate the damage frequency according to the operating conditions of the bearing.

[0023] A desirable aspect of the bearing diagnosis method may be such that, in the determination processing step, it is estimated that flaking has occurred when a peak value of signal intensity within a predetermined range that includes even multiples of the damage frequency exceeds a predetermined threshold value.

[0024] In a preferred aspect of the bearing diagnosis method, in the determination processing step, the peak value of the signal strength within a predetermined range that includes the damage frequency or an odd-numbered multiple of the damage frequency is designated as n1, and the peak value of the signal strength within a predetermined range that includes an even-numbered multiple of the damage frequency is designated as n2, and it is preferable that flaking be estimated to have occurred when the ratio expressed as n2 / n1 exceeds a predetermined threshold.

[0025] This makes it easier to detect when the size of flaking in the rotational direction approaches half the distance between the rolling elements, thereby improving the accuracy of estimating flaking.

[0026] In a preferred aspect of the bearing diagnosis method, in the judgment processing step, it is preferable that the integrated value of signal strength within a predetermined range that includes the damage frequency or odd multiples of the damage frequency is defined as S1, the integrated value of signal strength within a predetermined range that includes even multiples of the damage frequency is defined as S2, and when the ratio expressed as S2 / S1 exceeds a predetermined threshold, it is estimated that flaking has occurred.

[0027] This makes it easier to detect when the size of flaking in the rotational direction approaches half the distance between the rolling elements, thereby improving the accuracy of estimating flaking.

[0028] As a desirable aspect of the bearing diagnosis method, in the determination processing step, an integrated value of signal strength over the entire region of the frequency domain signal may be defined as S, a peak value of signal strength within a predetermined range including even multiples of the damage frequency may be defined as n2, and when a ratio expressed as n2 / S exceeds a predetermined threshold, it may be estimated that flaking has occurred.

[0029] As a desirable aspect of the bearing diagnosis method, in the determination processing step, an integrated value of signal strength over the entire region of the frequency domain signal may be defined as S, an integrated value of signal strength within a predetermined range including even multiples of the damage frequency may be defined as S2, and when a ratio expressed as S2 / S exceeds a predetermined threshold, it may be estimated that flaking has occurred.

[0030] In a preferred embodiment of the bearing diagnosis method, in the determination processing step, the effective value of the vibration signal may be defined as R, the peak value of the signal strength within a predetermined range that includes even multiples of the damage frequency may be defined as n2, and it may be estimated that flaking has occurred if the ratio expressed as n2 / R exceeds a predetermined threshold value.

[0031] As a desirable aspect of the bearing diagnosis method, in the determination processing step, the effective value of the vibration signal may be defined as R, the integrated value of the signal strength within a predetermined range including even multiples of the damage frequency may be defined as S2, and if the ratio expressed as S2 / R exceeds a predetermined threshold, it may be estimated that flaking has occurred. [Effects of the Invention]

[0032] According to the present invention, a bearing diagnostic device and a bearing diagnostic method are provided that are capable of estimating the occurrence of flaking. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a diagram showing an example of a schematic configuration of a bearing diagnostic system. [Figure 2] FIG. 2 is a block diagram showing an example of a bearing diagnosis device according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of envelope processing. [Figure 4] FIG. 4 is a diagram illustrating an example of a frequency domain signal after FFT processing. [Figure 5A] FIG. 5A is a conceptual diagram showing an example of flaking occurring on a raceway surface. [Figure 5B] FIG. 5B is a conceptual diagram showing an example in which the flaking that occurred on the raceway surface in FIG. 5A has progressed. [Figure 5C] FIG. 5C is a conceptual diagram showing an example in which the flaking that occurred on the raceway surface in FIG. 5A has progressed further than in FIG. 5B. [Figure 6A]FIG. 6A is a schematic image diagram showing the time domain signal in the first example shown in FIG. 5A. [Figure 6B] FIG. 6B is a schematic image diagram showing the time domain signal in the second example shown in FIG. 5B. [Figure 6C] FIG. 6C is a schematic image diagram showing the time domain signal of the third example shown in FIG. 5C. [Figure 7A] FIG. 7A is a schematic image diagram showing the frequency domain signal of the first example shown in FIG. 5A. [Figure 7B] FIG. 7B is a schematic image diagram showing the frequency domain signal of the second example shown in FIG. 5B. [Figure 7C] FIG. 7C is a schematic image diagram showing the frequency domain signal of the third example shown in FIG. 5C. [Figure 8] FIG. 8 is a flowchart showing an example of a bearing diagnosis process according to the first embodiment. [Figure 9A] FIG. 9A is a first conceptual diagram showing an example of the extraction process of the peak value n2. [Figure 9B] FIG. 9B is a second conceptual diagram showing an example of the process of extracting the peak value n2. [Figure 10] FIG. 10 is a diagram showing an example of time variation of the peak value n2. [Figure 11] FIG. 11 is a flowchart showing an example of a bearing diagnosis process according to the second embodiment. [Figure 12A] FIG. 12A is a conceptual diagram showing an example of the extraction process of the peak value n1. [Figure 12B] FIG. 12B is a conceptual diagram showing an example of the extraction process of the peak value n2. [Figure 13] FIG. 13 is a diagram showing an example of time variation of the ratio n2 / n1. [Figure 14] FIG. 14 is a flowchart showing an example of a bearing diagnosis process according to the third embodiment. [Figure 15A] FIG. 15A is a conceptual diagram showing an example of a frequency range when calculating the integrated value S1. [Figure 15B] FIG. 15B is a conceptual diagram showing an example of a frequency range when calculating the integrated value S2. [Figure 16] FIG. 16 is a diagram showing an example of time variation of the ratio S2 / S1. [Figure 17] FIG. 17 is a flowchart showing an example of a bearing diagnosis process according to the fourth embodiment. [Figure 18] FIG. 18 is a diagram showing an example of time variation of the ratio n2 / S. [Figure 19] FIG. 19 is a flowchart showing an example of a bearing diagnosis process according to the fifth embodiment. [Figure 20] FIG. 20 is a diagram showing an example of time variation of the ratio S2 / S. [Figure 21] FIG. 21 is a flowchart showing an example of a bearing diagnosis process according to the sixth embodiment. [Figure 22] FIG. 22 is a flowchart showing an example of a bearing diagnosis process according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments. Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

[0035] 1 is a diagram showing an example of the schematic configuration of a bearing diagnostic system 1. The bearing diagnostic system 1 includes a rolling bearing (hereinafter also simply referred to as a "bearing") 11 installed in a mechanical equipment 10, and a bearing diagnostic device 3.

[0036] Examples of the mechanical equipment 10 include railway vehicles, machine tools, wind power generation equipment, elevator equipment, etc. In the present disclosure, a bearing diagnostic device 3 estimates the occurrence state of flaking (scale-like peeling occurring on the surface of the raceway surface) on the raceway surface of the rolling element 113 of the bearing 11 based on a vibration signal acquired by a vibration sensor 2 provided on the mechanical equipment 10.

[0037] An example of the vibration sensor 2 is an acceleration sensor such as an acceleration pickup. The vibration sensor 2 may be installed in any position where it can detect vibrations that occur as the bearing 11 rotates. A vibration signal (e.g., acceleration) acquired by the vibration sensor 2 is input to the bearing diagnosis device 3. In addition to the acceleration sensor used in this embodiment, other sensors that can be used as the vibration sensor 2 include, for example, an AE (Acoustic Emission) sensor, an ultrasonic sensor, and a shock pulse sensor. Furthermore, sensors that can detect acceleration, speed, strain, stress, displacement, etc., and thereby equivalently detect vibrations and convert them into electrical signals can also be used as appropriate.

[0038] Furthermore, in addition to the vibration signals acquired by the vibration sensor 2, the operating conditions of the bearing 11 are input to the bearing diagnostic device 3. In the present disclosure, the operating conditions of the bearing 11 include an inner ring rotational frequency fr and a cage rotational frequency fc. For example, the inner ring rotational frequency fr and the cage rotational frequency fc are calculated from detection signals of various rotational speed sensors (not shown) provided in the mechanical equipment 10. These operating conditions of the bearing 11 (specifically, the inner ring rotational frequency fr and the cage rotational frequency fc) are used to calculate the damage frequency of the bearing 11, which will be described later.

[0039] Fig. 2 is a block diagram showing an example of a bearing diagnosis device according to an embodiment. As shown in Fig. 2, the bearing diagnosis device 3 according to the embodiment includes an AD conversion unit 31, an envelope processing unit 32, a frequency analysis processing unit 33, a judgment processing unit 34, and a data storage unit 35.

[0040] The AD conversion unit 31 converts the vibration signal (for example, acceleration) detected by the vibration sensor 2 into digital data.

[0041] The envelope processing unit 32 performs envelope processing (envelope detection processing) on ​​the vibration signal converted into digital data by the AD conversion unit 31, for example, by absolute value detection. Fig. 3 is a diagram showing an example of envelope processing. The dashed line shown in Fig. 3 indicates the vibration signal before envelope processing is performed, and the solid line indicates the time domain signal after envelope processing. Fig. 3 illustrates envelope processing by absolute value detection, but it is also possible to perform envelope processing on the vibration signal using, for example, a Hilbert transform.

[0042] The frequency analysis processing unit 33 performs a fast Fourier transform (FFT) process on the envelope-processed signal to convert it into a frequency-domain signal including signal strength for each frequency. Fig. 4 is a diagram showing an example of the frequency-domain signal after the FFT process.

[0043] The determination processing unit 34 calculates the damage frequency of the bearing 11 based on the above-mentioned operating conditions (inner ring rotational frequency fr and cage rotational frequency fc) as a premise for the bearing diagnostic processing according to the present disclosure. Each parameter (design specification data) of the bearing 11 used when calculating the damage frequency of the bearing 11 is stored in advance in the data storage unit 35. An example of the data storage unit 35 is a storage device such as a memory. The determination processing unit 34 may also be configured to store the results of the bearing diagnostic processing described below in the data storage unit 35.

[0044] The damage frequency caused by damage to the inner ring 111 (hereinafter also simply referred to as the "inner ring damage frequency") can be expressed as the value obtained by multiplying the relative rotational frequency fi between the inner ring rotational frequency fr and the cage rotational frequency fc by the number of rolling elements Z (=Z×fi, hereinafter also simply referred to as "Zfi"). The inner ring damage frequency Zfi is given by the following equation (1) using the rolling element diameter Da, pitch circle diameter dm, and contact angle α.

[0045]

number

[0046] The damage frequency caused by damage to the outer ring 112 (hereinafter also simply referred to as the "outer ring damage frequency") can be expressed as the cage rotation frequency fc multiplied by the number of rolling elements Z (=Z×fc, hereinafter also simply referred to as "Zfc"). The outer ring damage frequency Zfc is given by the following equation (2).

[0047]

number

[0048] The flaking to be estimated in the bearing 11 of the present disclosure is expected to occur both on the raceway surface 111a of the inner ring 111 (hereinafter also simply referred to as the "inner ring raceway surface") and on the raceway surface 112a of the outer ring 112 (hereinafter also simply referred to as the "outer ring raceway surface").

[0049] In the following explanation, an example of estimating flaking occurring on the inner ring raceway surface 111a will be described. In the following explanation, "damage frequency Zfi" indicates the inner ring damage frequency, but when estimating flaking occurring on the outer ring raceway surface 112a, it can be interpreted as the outer ring damage frequency.

[0050] Flaking that occurs on the raceway surface (here, inner ring raceway surface 111a) progresses in the direction of rotation over time. Fig. 5A is a conceptual diagram showing an example of flaking that has occurred on the raceway surface. Fig. 5B is a conceptual diagram showing an example of the progress of the flaking that has occurred on the raceway surface in Fig. 5A. Fig. 5C is a conceptual diagram showing an example of the progress of the flaking that has occurred on the raceway surface in Fig. 5A compared to Fig. 5B.

[0051] 5A, 5B, and 5C show examples in which flaking has occurred on inner ring raceway surface 111a. For ease of explanation, the alignment direction of rolling elements 113 is shown as a straight line in FIGS. 5A, 5B, and 5C.

[0052] 5A, 5B, and 5C, the distance between adjacent rolling elements 113 (hereinafter also referred to simply as "distance between rolling elements") is 1 pitch. The example shown in FIG. 5A shows an example in which the flaking size (A-B distance) in the rotational direction on the raceway surface (here, the inner ring raceway surface 111a) is less than 0.5 pitch. The example shown in FIG. 5B shows an example in which the flaking size (A-B distance) in the rotational direction has progressed to 0.5 pitch. The example shown in FIG. 5C shows an example in which the flaking size (A-B distance) in the rotational direction has progressed further than in FIG. 5B and has exceeded 0.5 pitch.

[0053] Figure 6A is a schematic image diagram showing the time domain signal in the first example shown in Figure 5A, Figure 6B is a schematic image diagram showing the time domain signal in the second example shown in Figure 5B, and Figure 6C is a schematic image diagram showing the time domain signal in the third example shown in Figure 5C.

[0054] Figure 7A is a schematic diagram showing a frequency domain signal of the first example shown in Figure 5A, Figure 7B is a schematic diagram showing a frequency domain signal of the second example shown in Figure 5B, and Figure 7C is a schematic diagram showing a frequency domain signal of the third example shown in Figure 5C.

[0055] When flaking that occurs on the raceway surface (here, inner ring raceway surface 111a) progresses in the direction of rotation and the flaking size (distance between A and B) increases, vibrations occur at two points, one end (point A) and the other end (point B) of the flaking in the rotational direction, as the bearing 11 rotates. T(A) shown in Figures 6A, 6B, and 6C indicates the period of vibration that occurs between each rolling element 113 and the inner ring 112 at one end (point A) of the flaking that occurs on the raceway surface (here, inner ring raceway surface 111a). T(B) shown in Figures 6A, 6B, and 6C indicates the period of vibration that occurs between each rolling element 113 and the inner ring 112 at the other end (point B) of the flaking that occurs on the raceway surface (here, inner ring raceway surface 111a).

[0056] As shown in FIG. 5B, when the size of flaking (distance between A and B) in the rotational direction of flaking that has occurred on the raceway surface (here, the inner ring raceway surface 111a) grows to 0.5 pitches, the vibration period T(A) at point A and the vibration period T(B) at point B are shifted by 0.5 pitches from each other. As a result, as shown in FIG. 6B, vibration components with one period equal to half the vibration period T(A) at point A and the vibration period T(B) at point B (T(A) / 2, T(B) / 2) appear in the time-domain signal. As a result, the signal intensity of the double harmonic 2Zfi of the damage frequency Zfi that appears in the frequency-domain signal increases, as shown in FIG. 7B.

[0057] The signal strength of the second harmonic 2Zfi of this damage frequency Zfi increases as the flaking size (AB distance) in the rotational direction of the flaking on the raceway surface (here, the inner ring raceway surface 111a) approaches 0.5 pitch, and decreases as the flaking size (AB distance) in the rotational direction of the flaking on the raceway surface (here, the inner ring raceway surface 111a) deviates from 0.5 pitch. The bearing diagnostic device 3 and bearing diagnostic method according to the present disclosure utilize this characteristic to estimate the occurrence of flaking on the raceway surface (here, the inner ring raceway surface 111a). The flaking estimation method according to each embodiment will be described below.

[0058] (Embodiment 1) FIG. 8 is a flowchart showing an example of a bearing diagnosis process according to the first embodiment.

[0059] The AD conversion processing unit 31 performs AD conversion processing on the vibration signal acquired by the vibration sensor 2 (step S101). The envelope processing unit 32 performs envelope processing on the AD converted vibration signal (step S102). The frequency analysis processing unit 33 performs FFT processing on the time domain signal after envelope processing, and performs frequency spectrum analysis processing (step S103).

[0060] The determination processing unit 34 extracts a peak value n2 of the signal intensity within a predetermined frequency range f_range that includes the second harmonic 2Zfi of the damage frequency Zfi (step S104), and determines whether the peak value n2 is equal to or less than a predetermined threshold value nth (step S105). If the peak value n2 is equal to or less than the predetermined threshold value nth (step S105; Yes), the bearing diagnosis process in the bearing diagnosis device 3 ends. If the peak value n2 exceeds the predetermined threshold value nth (step S105; No), the determination processing unit 34 determines that flaking has occurred in the bearing 11 (step S106), outputs the determination result (step S107), and ends the bearing diagnosis process in the bearing diagnosis device 3. The determination result by the determination processing unit 34 may be output to, for example, the data storage unit 35, or an external device (not shown) to which the bearing diagnosis device 3 is connected.

[0061] Fig. 9A is a first conceptual diagram showing an example of the extraction process of the peak value n2. Fig. 9B is a second conceptual diagram showing an example of the extraction process of the peak value n2. Fig. 9A shows an example in which the peak value n2 of the signal strength exceeds the threshold value nth within the frequency range f_range of ±5 Hz of the second harmonic 2Zfi of the damage frequency Zfi. Fig. 9B shows an example in which the peak value n2 of the signal strength is equal to or less than the threshold value nth within the frequency range f_range of -5 Hz to +5 Hz of the second harmonic 2Zfi of the damage frequency Zfi (2ZFi-5 Hz≦f≦2ZFi+5 Hz).

[0062] In FIGS. 9A and 9B, the frequency range f_range for extracting the peak value n2 is set to a range of ±5 Hz of the second harmonic 2Zfi of the damage frequency Zfi (2ZFi-5 Hz≦f≦2ZFi+5 Hz), but is not limited to this.

[0063] It is expected that the frequency components appearing as peak values ​​in the frequency domain signal will deviate approximately within a range of ±10% from the damage frequency Zfi and its second harmonic 2Zfi calculated based on the operating conditions (inner ring rotational frequency fr and cage rotational frequency fc) and various parameters (design specification data) of the bearing 11. For this reason, the frequency range f_range for extracting the peak value n2 may be, for example, within a range of ±10% of the second harmonic 2Zfi of the damage frequency Zfi.

[0064] Fig. 10 is a diagram showing an example of time variation of the peak value n2. In Fig. 10, the horizontal axis represents the operating time of the bearing 11. In the gray time range shown in Fig. 10, it is assumed that the size of the flaking in the rotational direction (for example, the distance between A and B of the flaking that has occurred on the inner ring raceway surface 111a shown in Fig. 5B) is approaching 0.5 pitch.

[0065] In the first embodiment, the signal intensity of the frequency component corresponding to the double harmonic 2Zfi of the damage frequency Zfi is extracted as a peak value n2, and a threshold determination is performed on the peak value n2. Because the double harmonic 2Zfi of the damage frequency Zfi is also a harmonic component of the damage frequency Zfi, the peak value n2 extracted as the signal intensity of the frequency component corresponding to the double harmonic 2Zfi of the damage frequency Zfi is high even outside the time range in which the flaking size in the rotational direction is expected to approach 0.5 pitches, as shown in Fig. 10.

[0066] It is also possible to extract the signal intensity of a frequency component corresponding to an even harmonic, such as a fourth harmonic or a sixth harmonic, as the peak value n2, instead of the second harmonic 2Zfi of the damage frequency Zfi.

[0067] (Embodiment 2) 11 is a flowchart showing an example of a bearing diagnosis process according to embodiment 2. Here, processes that differ from those in embodiment 1 described above will be described in detail, and detailed descriptions of processes that are the same as those in embodiment 1 described above may be omitted.

[0068] The determination processor 34 extracts a signal intensity peak value n1 within a predetermined frequency range f1_range that includes the damage frequency Zfi and a signal intensity peak value n2 within a predetermined frequency range f2_range that includes the second harmonic 2Zfi of the damage frequency Zfi (step S104a), and determines whether the ratio expressed by n2 / n1 is equal to or less than a predetermined threshold n2 / n1th (step S105a). If the ratio n2 / n1 is equal to or less than the predetermined threshold n2 / n1th (step S105a; Yes), the bearing diagnosis process in the bearing diagnosis device 3 ends. If the ratio n2 / n1 exceeds the predetermined threshold n2 / n1th (step S105a; No), the determination processor 34 determines that flaking has occurred in the bearing 11 (step S106), outputs the determination result (step S107), and ends the bearing diagnosis process in the bearing diagnosis device 3.

[0069] Fig. 12A is a conceptual diagram showing an example of a process for extracting a peak value n1. Fig. 12B is a conceptual diagram showing an example of a process for extracting a peak value n2. Fig. 12A shows an example in which the signal strength of a frequency at which the signal strength is maximum within a frequency range f1_range (ZFi-5Hz≦f≦ZFi+5Hz) of ±5 Hz of the damage frequency Zfi is set as the peak value n1. Fig. 12B shows an example in which the signal strength of a frequency at which the signal strength is maximum within a frequency range f2_range (2ZFi-5Hz≦f≦2ZFi+5Hz) of ±5 Hz of the second harmonic 2Zfi of the damage frequency Zfi is set as the peak value n2.

[0070] 12A, the frequency range f1_range for extracting the peak value n1 is set to a range of ±5 Hz of the damage frequency Zfi (Zfi-5 Hz≦f≦Zfi+5 Hz), but is not limited to this. Also, in FIG. 12B, the frequency range f2_range for extracting the peak value n2 is set to a range of ±5 Hz of the second harmonic 2Zfi of the damage frequency Zfi (2Zfi-5 Hz≦f≦2Zfi+5 Hz), but is not limited to this.

[0071] It is expected that the frequency components appearing as peak values ​​in the frequency domain signal will deviate approximately within a range of ±10% from the damage frequency Zfi and its second harmonic 2Zfi calculated based on the operating conditions (inner ring rotational frequency fr and cage rotational frequency fc) and various parameters (design specification data) of the bearing 11. For this reason, the frequency range f1_range from which the peak value n1 is extracted may be, for example, a range of ±10% of the damage frequency Zfi, and the frequency range f2_range from which the peak value n2 is extracted may be, for example, a range of ±10% of the second harmonic 2Zfi of the damage frequency Zfi.

[0072] Fig. 13 is a diagram showing an example of time variation of the ratio n2 / n1. In Fig. 13, the horizontal axis represents the operating time of the bearing 11. In the gray time range shown in Fig. 13, it is assumed that the size of the flaking in the rotational direction (for example, the distance between A and B of the flaking that has occurred on the inner ring raceway surface 111a shown in Fig. 5B) is approaching 0.5 pitch.

[0073] In the second embodiment, the signal intensity of the frequency component corresponding to the damage frequency Zfi is extracted as a peak value n1, and the signal intensity of the frequency component corresponding to the double harmonic 2Zfi of the damage frequency Zfi is extracted as a peak value n2. A threshold determination is then performed on the ratio n2 / n1 of these values. In the double harmonic 2Zfi of the damage frequency Zfi, the component corresponding to the second harmonic component of the damage frequency Zfi is canceled out by calculating the ratio with the damage frequency Zfi. This results in a larger fluctuation in the ratio n2 / n1 as flaking progresses. As shown in FIG. 13, the ratio n2 / n1 exhibits a relatively low value outside the time range in which the flaking rotational size is expected to approach 0.5 pitches. This facilitates the setting of the threshold n2 / n1th. Furthermore, it becomes easier to detect when the flaking rotational size is approaching 0.5 pitches, thereby improving the accuracy of flaking estimation.

[0074] In addition, instead of the damage frequency Zfi, the signal intensity of a frequency component corresponding to an odd multiple such as a third or fifth multiple of the damage frequency Zfi may be extracted as the peak value n1, and instead of the second multiple 2Zfi of the damage frequency Zfi, the signal intensity of a frequency component corresponding to an even multiple such as a fourth or sixth multiple may be extracted as the peak value n2.

[0075] (Embodiment 3) 14 is a flowchart showing an example of a bearing diagnosis process according to embodiment 3. Here, processes that differ from those in the above-described embodiments will be described in detail, and detailed descriptions of processes that are the same as those in the above-described embodiments may be omitted.

[0076] The determination processor 34 calculates an integrated value S1 of the signal strength within a predetermined frequency range f1_range that includes the damage frequency Zfi, and an integrated value S2 of the signal strength within a predetermined frequency range f2_range that includes the second harmonic 2Zfi of the damage frequency Zfi (step S104b), and determines whether the ratio expressed by S2 / S1 is equal to or less than a predetermined threshold value S2 / S1th (step S105b). If the ratio S2 / S1 is equal to or less than the predetermined threshold value S2 / S1th (step S105b; Yes), the bearing diagnosis process in the bearing diagnosis device 3 ends. If the ratio S2 / S1 exceeds the predetermined threshold value S2 / S1th (step S105b; No), the determination processor 34 determines that flaking has occurred in the bearing 11 (step S106), outputs the determination result (step S107), and ends the bearing diagnosis process in the bearing diagnosis device 3.

[0077] Fig. 15A is a conceptual diagram showing an example of a frequency range when calculating an integrated value S1. Fig. 15B is a conceptual diagram showing an example of a frequency range when calculating an integrated value S2. Fig. 15A shows an example of calculating an integrated value S1 of signal strength within a frequency range f1_range (ZFi-5Hz≦f≦ZFi+5Hz) of ±5 Hz of the damage frequency Zfi. Fig. 15B shows an example of calculating an integrated value S2 of signal strength within a frequency range f2_range (2ZFi-5Hz≦f≦2ZFi+5Hz) of ±5 Hz of the second harmonic 2Zfi of the damage frequency Zfi.

[0078] In Fig. 15A, the frequency range f1_range when calculating the integrated value S1 is set to a range of ±5 Hz of the damage frequency Zfi (ZFi-5 Hz≦f≦ZFi+5 Hz), but is not limited to this. Also, in Fig. 15B, the frequency range f2_range when calculating the integrated value S2 is set to a range of ±5 Hz of the second harmonic 2Zfi of the damage frequency Zfi (2ZFi-5 Hz≦f≦2ZFi+5 Hz), but is not limited to this.

[0079] It is expected that the frequency components appearing as peak values ​​in the frequency domain signal will deviate approximately within a range of ±10% from the damage frequency Zfi and its second harmonic 2Zfi calculated based on the operating conditions (inner ring rotational frequency fr and cage rotational frequency fc) and various parameters (design specification data) of the bearing 11. For this reason, the frequency range f1_range used to calculate the integrated value S1 may be, for example, a range of ±10% of the damage frequency Zfi, and the frequency range f2_range used to calculate the integrated value S2 may be, for example, a range of ±10% of the second harmonic 2Zfi of the damage frequency Zfi.

[0080] Fig. 16 is a diagram showing an example of time variation of the ratio S2 / S1. In Fig. 16, the horizontal axis represents the operating time of the bearing 11. In the gray time range shown in Fig. 13, it is assumed that the size of the flaking in the rotational direction (for example, the distance between A and B of the flaking that has occurred on the inner ring raceway surface 111a shown in Fig. 5B) is approaching 0.5 pitch.

[0081] In the third embodiment, an integrated value S1 of signal strength including a frequency component corresponding to the damage frequency Zfi is calculated, and an integrated value S2 of signal strength including a frequency component corresponding to the double harmonic 2Zfi of the damage frequency Zfi is calculated. A threshold determination is then performed on the ratio S2 / S1 of these values. In the double harmonic 2Zfi of the damage frequency Zfi, the component corresponding to the second harmonic component of the damage frequency Zfi is canceled out by calculating the ratio with the damage frequency Zfi. This results in a larger fluctuation in the ratio S2 / S1 as flaking progresses. As shown in FIG. 16, the ratio S2 / S1 exhibits a relatively low value outside the time range in which the flaking rotational direction peel size is expected to approach 0.5 pitches. This facilitates the setting of the threshold S2 / S1th. Furthermore, it becomes easier to detect when the flaking rotational direction peel size is approaching 0.5 pitches, thereby improving the accuracy of flaking estimation.

[0082] In addition, instead of the damage frequency Zfi, it is also possible to calculate an integrated value S1 of signal strength including frequency components corresponding to odd harmonics such as the third or fifth harmonics of the damage frequency Zfi, or instead of the second harmonics 2Zfi of the damage frequency Zfi, it is also possible to calculate an integrated value S2 of signal strength including frequency components corresponding to even harmonics such as the fourth or sixth harmonics.

[0083] (Embodiment 4) 17 is a flowchart showing an example of a bearing diagnosis process according to embodiment 4. Here, processes that differ from those in the above-described embodiments will be described in detail, and detailed descriptions of processes that are the same as those in the above-described embodiments may be omitted.

[0084] The determination processor 34 calculates an integrated value S of the signal strength over the entire frequency domain signal, extracts a peak value n2 of the signal strength within a predetermined frequency range including the second harmonic 2Zfi of the damage frequency Zfi (step S104c), and determines whether the ratio expressed by n2 / S is equal to or less than a predetermined threshold value n2 / Sth (step S105c). If the ratio n2 / S is equal to or less than the predetermined threshold value n2 / Sth (step S105c; Yes), the bearing diagnosis process in the bearing diagnosis device 3 ends. If the ratio n2 / S exceeds the predetermined threshold value n2 / Sth (step S105c; No), the determination processor 34 determines that flaking has occurred in the bearing 11 (step S106), outputs the determination result (step S107), and ends the bearing diagnosis process in the bearing diagnosis device 3.

[0085] The frequency range for extracting the peak value n2 may be, for example, a range of ±5 Hz of the double wave 2Zfi of the damage frequency Zfi (2Zfi-5 Hz≦f≦2Zfi+5 Hz), as in the first and second embodiments, or may be, for example, a range of ±10% of the double wave 2Zfi of the damage frequency Zfi. The frequency range for extracting the peak value n2 is not limited.

[0086] Fig. 18 is a diagram showing an example of time variation of the ratio n2 / S. In Fig. 18, the horizontal axis represents the operating time of the bearing 11. In the gray time range shown in Fig. 18, it is assumed that the size of the flaking in the rotational direction (for example, the distance between A and B of the flaking that has occurred on the inner ring raceway surface 111a shown in Fig. 5B) is approaching 0.5 pitch.

[0087] In the fourth embodiment, the integrated value S of the signal intensity in the entire frequency domain signal is calculated, the signal intensity of the frequency component corresponding to the double harmonic 2Zfi of the damage frequency Zfi is extracted as a peak value n2, and a threshold is determined for the ratio n2 / S of these. Because the integrated value S includes all frequency components and is relatively large compared to the double harmonic 2Zfi of the damage frequency Zfi, the component corresponding to the second harmonic component of the damage frequency Zfi is not canceled out, and as shown in Fig. 18, the value remains high even outside the time range in which the flaking size in the rotational direction is expected to approach 0.5 pitches.

[0088] It is also possible to extract the signal intensity of a frequency component corresponding to an even harmonic, such as a fourth harmonic or a sixth harmonic, as the peak value n2, instead of the second harmonic 2Zfi of the damage frequency Zfi.

[0089] (Embodiment 5) 19 is a flowchart showing an example of a bearing diagnosis process according to embodiment 5. Here, processes that differ from those in the above-described embodiments will be described in detail, and detailed descriptions of processes that are the same as those in the above-described embodiments may be omitted.

[0090] The determination processing unit 34 calculates an integrated value S of the signal strength over the entire frequency domain signal and an integrated value S2 of the signal strength within a predetermined frequency range including the second harmonic 2Zfi of the damage frequency Zfi (step S104d), and determines whether the ratio represented by S2 / S is equal to or less than a predetermined threshold value S2 / Sth (step S105d). If the ratio S2 / S is equal to or less than the predetermined threshold value S2 / Sth (step S105d; Yes), the bearing diagnosis process in the bearing diagnosis device 3 ends. If the ratio S2 / S exceeds the predetermined threshold value S2 / Sth (step S105d; No), the determination processing unit 34 determines that flaking has occurred in the bearing 11 (step S106), outputs the determination result (step S107), and ends the bearing diagnosis process in the bearing diagnosis device 3.

[0091] The frequency range when calculating the integrated value S2 may be, for example, a range of ±5 Hz of the double wave 2Zfi of the damage frequency Zfi (2ZFi-5 Hz≦f≦2ZFi+5 Hz), as in the third embodiment, or may be, for example, a range of ±10% of the double wave 2Zfi of the damage frequency Zfi. The frequency range when calculating the integrated value S2 is not limited.

[0092] Fig. 20 is a diagram showing an example of time variation of the ratio S2 / S. In Fig. 20, the horizontal axis represents the operating time of the bearing 11. In the gray time range shown in Fig. 20, it is assumed that the size of the flaking in the rotational direction (for example, the distance between A and B of the flaking that has occurred on the inner ring raceway surface 111a shown in Fig. 5B) is approaching 0.5 pitch.

[0093] In the fifth embodiment, an integrated value S of the signal intensity in the entire frequency domain signal and an integrated value S2 of the signal intensity of the frequency component corresponding to the double harmonic 2Zfi of the damage frequency Zfi are calculated, and a threshold is determined for the ratio S2 / S of these values. Because the integrated value S includes all frequency components and is relatively large compared to the double harmonic 2Zfi of the damage frequency Zfi, the component corresponding to the second harmonic component of the damage frequency Zfi is not canceled out, and as shown in Fig. 20, the integrated value S remains high even outside the time range in which the flaking size in the rotational direction is expected to approach 0.5 pitches.

[0094] It is also possible to calculate the integrated value S2 of the signal intensity including frequency components corresponding to even harmonics such as fourth and sixth harmonics instead of the second harmonics 2Zfi of the damage frequency Zfi.

[0095] (Embodiment 6) 21 is a flowchart showing an example of a bearing diagnosis process according to embodiment 6. Here, processes that differ from those in the above-described embodiments will be described in detail, and detailed descriptions of processes that are similar to those in the above-described embodiments may be omitted.

[0096] The determination processor 34 calculates the effective value R of the vibration signal, extracts the peak value n2 of the signal strength within a predetermined frequency range including the second harmonic 2Zfi of the damage frequency Zfi (step S104e), and determines whether the ratio expressed by n2 / R is equal to or less than a predetermined threshold value n2 / Rth (step S105e). If the ratio n2 / R is equal to or less than the predetermined threshold value n2 / Rth (step S105e; Yes), the bearing diagnosis process in the bearing diagnosis device 3 ends. If the ratio n2 / R exceeds the predetermined threshold value n2 / Rth (step S105e; No), the determination processor 34 determines that flaking has occurred in the bearing 11 (step S106), outputs the determination result (step S107), and ends the bearing diagnosis process in the bearing diagnosis device 3.

[0097] The frequency range for extracting the peak value n2 may be, for example, a range of ±5 Hz of the double wave 2Zfi of the damage frequency Zfi (2ZFi-5 Hz≦f≦2ZFi+5 Hz), as in the first, second, and fourth embodiments, or may be, for example, a range of ±10% of the double wave 2Zfi of the damage frequency Zfi. The frequency range for extracting the peak value n2 is not limited.

[0098] In the sixth embodiment, instead of the integrated value S of the signal strength over the entire frequency domain signal in the fourth embodiment, the effective value R of the vibration signal is calculated, and a threshold determination is made for the ratio n2 / R. Since the effective value R of the vibration signal includes all frequency components, the component corresponding to the second harmonic component of the damage frequency Zfi is not canceled out, as in the fourth embodiment, and the value remains high even outside the time range in which the flaking size in the rotational direction is expected to approach 0.5 pitches.

[0099] It is also possible to extract the signal intensity of a frequency component corresponding to an even harmonic, such as a fourth harmonic or a sixth harmonic, as the peak value n2, instead of the second harmonic 2Zfi of the damage frequency Zfi.

[0100] (Embodiment 7) 22 is a flowchart showing an example of a bearing diagnosis process according to embodiment 7. Here, processes that differ from those in the above-described embodiments will be described in detail, and detailed descriptions of processes that are the same as those in the above-described embodiments may be omitted.

[0101] The determination processing unit 34 calculates the effective value R of the vibration signal and an integrated value S2 of the signal strength within a predetermined frequency range including the second harmonic 2Zfi of the damage frequency Zfi (step S104f), and determines whether the ratio represented by S2 / R is equal to or less than a predetermined threshold value S2 / Rth (step S105f). If the ratio S2 / R is equal to or less than the predetermined threshold value S2 / Rth (step S105f; Yes), the bearing diagnosis process in the bearing diagnosis device 3 ends. If the ratio S2 / R exceeds the predetermined threshold value S2 / Rth (step S105f; No), the determination processing unit 34 determines that flaking has occurred in the bearing 11 (step S106), outputs the determination result (step S107), and ends the bearing diagnosis process in the bearing diagnosis device 3.

[0102] The frequency range when calculating the integrated value S2 may be, for example, a range of ±5 Hz of the double wave 2Zfi of the damage frequency Zfi (2ZFi-5 Hz≦f≦2ZFi+5 Hz), as in the third and fifth embodiments, or may be, for example, a range of ±10% of the double wave 2Zfi of the damage frequency Zfi. There is no limitation to the frequency range when calculating the integrated value S2.

[0103] In the seventh embodiment, instead of the integrated value S of the signal strength over the entire frequency domain signal in the fifth embodiment, the effective value R of the vibration signal is calculated, and a threshold determination is made for the ratio S / R. Since the effective value R of the vibration signal includes all frequency components, the component corresponding to the second harmonic component of the damage frequency Zfi is not canceled out, as in the fifth embodiment, and the value remains high even outside the time range in which the flaking size in the rotational direction is expected to approach 0.5 pitches.

[0104] It is also possible to calculate the integrated value S2 of the signal intensity including frequency components corresponding to even harmonics such as fourth and sixth harmonics instead of the second harmonics 2Zfi of the damage frequency Zfi.

[0105] By using the bearing diagnosis processing according to each of the above-described embodiments, it is possible to estimate that flaking has occurred on the raceway surface of the bearing 11 before it progresses and reaches half the distance (0.5 pitch) between the rolling elements (1 pitch) on the raceway surface of the bearing 11. This makes it possible to determine that the bearing 11 needs to be replaced before damage to the bearing 11 progresses to the point where it becomes unusable. [Explanation of symbols]

[0106] 1 Bearing diagnostic system 2. Vibration Sensor 3 Bearing diagnostic equipment 10. Machinery and Equipment 11 Bearings 31 AD conversion section 32 Envelope processing section 33 Frequency analysis processing section 34 Judgment processing unit 35 Data storage section 111 Inner circle 111a Raceway surface (inner ring raceway surface) 112 outer ring 112a Raceway surface (outer ring raceway surface) 113 Rolling elements

Claims

1. A bearing diagnostic device that diagnoses the condition of a bearing provided in mechanical equipment, an envelope processing unit that performs envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis processing unit that performs a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal including signal strength for each frequency; a determination processing unit that estimates the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; Equipped with the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; The determination processing unit calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired; When a peak value of the signal intensity within a predetermined range including even multiples of the damage frequency exceeds a predetermined threshold, it is estimated that flaking has occurred. Bearing diagnostic equipment.

2. A bearing diagnostic device that diagnoses the condition of a bearing provided in mechanical equipment, an envelope processing unit that performs envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis processing unit that performs a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal including signal strength for each frequency; a determination processing unit that estimates the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; Equipped with the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; The determination processing unit calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired; The peak value of the signal strength within a predetermined range including the damage frequency or an odd multiple of the damage frequency is defined as n1, The peak value of the signal strength within a predetermined range including even multiples of the damage frequency is defined as n2, If the ratio expressed by n2 / n1 exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic equipment.

3. A bearing diagnostic device that diagnoses the condition of a bearing provided in mechanical equipment, an envelope processing unit that performs envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis processing unit that performs a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal including signal strength for each frequency; a determination processing unit that estimates the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; Equipped with the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; The determination processing unit calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired; S1 is an integrated value of the signal strength within a predetermined range including the damage frequency or an odd multiple of the damage frequency, The integrated value of the signal intensity within a predetermined range including even multiples of the damage frequency is defined as S2, If the ratio S2 / S1 exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic equipment.

4. A bearing diagnostic device that diagnoses the condition of a bearing provided in mechanical equipment, an envelope processing unit that performs envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis processing unit that performs a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal including signal strength for each frequency; a determination processing unit that estimates the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; Equipped with the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; The determination processing unit calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired; The integrated value of the signal strength in the entire frequency domain signal is S, The peak value of the signal strength within a predetermined range including even multiples of the damage frequency is defined as n2, Flaking is assumed to have occurred if the ratio represented by n2 / S exceeds a predetermined threshold. Bearing diagnostic equipment.

5. A bearing diagnostic device that diagnoses the condition of a bearing provided in mechanical equipment, an envelope processing unit that performs envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis processing unit that performs a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal including signal strength for each frequency; a determination processing unit that estimates the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; Equipped with the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; The determination processing unit calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired; The integrated value of the signal strength in the entire frequency domain signal is S, The integrated value of the signal intensity within a predetermined range including even multiples of the damage frequency is defined as S2, If the ratio S2 / S exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic equipment.

6. A bearing diagnostic device that diagnoses the condition of a bearing provided in mechanical equipment, an envelope processing unit that performs envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis processing unit that performs a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal including signal strength for each frequency; a determination processing unit that estimates the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; Equipped with the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; The determination processing unit calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired; The effective value of the vibration signal is R, The peak value of the signal strength within a predetermined range including even multiples of the damage frequency is defined as n2, If the ratio represented by n2 / R exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic equipment.

7. A bearing diagnostic device that diagnoses the condition of a bearing provided in mechanical equipment, an envelope processing unit that performs envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis processing unit that performs a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal including signal strength for each frequency; a determination processing unit that estimates the occurrence of flaking based on the signal strength of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; Equipped with the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; The determination processing unit calculating the damage frequency based on the operating conditions of the bearing when the vibration signal is acquired; The effective value of the vibration signal is R, The integrated value of the signal intensity within a predetermined range including even multiples of the damage frequency is defined as S2, If the ratio S2 / R exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic equipment.

8. A bearing diagnosis method for diagnosing the condition of a bearing provided in mechanical equipment, comprising: an envelope processing step of performing envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis step of performing a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; a determination processing step of estimating the occurrence of flaking based on the signal intensity of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; and the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; a damage frequency calculation step of calculating the damage frequency based on an operating condition of the bearing when the vibration signal is acquired, In the determination processing step, When a peak value of the signal intensity within a predetermined range including even multiples of the damage frequency exceeds a predetermined threshold, it is estimated that flaking has occurred. Bearing diagnostic methods.

9. A bearing diagnosis method for diagnosing the condition of a bearing provided in mechanical equipment, comprising: an envelope processing step of performing envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis step of performing a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; a determination processing step of estimating the occurrence of flaking based on the signal intensity of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; and a damage frequency calculation step of calculating the damage frequency based on an operating condition of the bearing when the vibration signal is acquired, In the determination processing step, The peak value of the signal strength within a predetermined range including the damage frequency or an odd multiple of the damage frequency is defined as n1, The peak value of the signal strength within a predetermined range including even multiples of the damage frequency is defined as n2, If the ratio expressed by n2 / n1 exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic methods.

10. A bearing diagnosis method for diagnosing the condition of a bearing provided in mechanical equipment, comprising: an envelope processing step of performing envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis step of performing a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; a determination processing step of estimating the occurrence of flaking based on the signal intensity of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; and a damage frequency calculation step of calculating the damage frequency based on an operating condition of the bearing when the vibration signal is acquired, In the determination processing step, S1 is an integrated value of the signal strength within a predetermined range including the damage frequency or an odd multiple of the damage frequency, The integrated value of the signal intensity within a predetermined range including even multiples of the damage frequency is defined as S2, If the ratio S2 / S1 exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic methods.

11. A bearing diagnosis method for diagnosing the condition of a bearing provided in mechanical equipment, comprising: an envelope processing step of performing envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis step of performing a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; a determination processing step of estimating the occurrence of flaking based on the signal intensity of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; and a damage frequency calculation step of calculating the damage frequency based on an operating condition of the bearing when the vibration signal is acquired, In the determination processing step, The integrated value of the signal strength in the entire frequency domain signal is S, The peak value of the signal strength within a predetermined range including even multiples of the damage frequency is defined as n2, Flaking is assumed to have occurred if the ratio represented by n2 / S exceeds a predetermined threshold. Bearing diagnostic methods.

12. A bearing diagnosis method for diagnosing the condition of a bearing provided in mechanical equipment, comprising: an envelope processing step of performing envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis step of performing a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; a determination processing step of estimating the occurrence of flaking based on the signal intensity of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; and a damage frequency calculation step of calculating the damage frequency based on an operating condition of the bearing when the vibration signal is acquired, In the determination processing step, The integrated value of the signal strength in the entire frequency domain signal is S, The integrated value of the signal intensity within a predetermined range including even multiples of the damage frequency is defined as S2, If the ratio S2 / S exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic methods.

13. A bearing diagnosis method for diagnosing the condition of a bearing provided in mechanical equipment, comprising: an envelope processing step of performing envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis step of performing a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; a determination processing step of estimating the occurrence of flaking based on the signal intensity of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; and a damage frequency calculation step of calculating the damage frequency based on an operating condition of the bearing when the vibration signal is acquired, In the determination processing step, The effective value of the vibration signal is R, The peak value of the signal strength within a predetermined range including even multiples of the damage frequency is defined as n2, If the ratio represented by n2 / R exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic methods.

14. A bearing diagnosis method for diagnosing the condition of a bearing provided in mechanical equipment, comprising: an envelope processing step of performing envelope processing on the vibration signal acquired by the vibration sensor; a frequency analysis step of performing a fast Fourier transform on the time domain signal after the envelope processing to convert it into a frequency domain signal containing signal strength for each frequency; a determination processing step of estimating the occurrence of flaking based on the signal intensity of even multiple waves of a damage frequency caused by at least damage occurring on the raceway surface of the bearing; and the signal strength of the even-numbered harmonic of the damage frequency is maximized when the size of the flaking in the rotational direction on the raceway surface of the bearing is 0.5 pitches, with the distance between the rolling elements of the bearing being 1 pitch; a damage frequency calculation step of calculating the damage frequency based on an operating condition of the bearing when the vibration signal is acquired, In the determination processing step, The effective value of the vibration signal is R, The integrated value of the signal intensity within a predetermined range including even multiples of the damage frequency is defined as S2, If the ratio S2 / R exceeds a predetermined threshold, it is assumed that flaking has occurred. Bearing diagnostic methods.

Images